In order to easily fasten or unfasten a button for clothes, sewed to the clothes such as a suit or a Y-shirt, into or from a button hole of the clothes, a proper gap needs to be formed between the clothes and the button. For this reason, another thread winds around a sewing thread protruded from the rear surface of the button facing the clothes, and is then knotted.
In case that the button is sewed to the clothes as described above, the sewing thread of the button requires a designated solidity and a designated flexibility, thus preventing the button from sagging and allowing the button to be easily inserted into the button holes of the clothes. Further, the button, which was sewed to the clothes by an apparatus, must be fixed to the clothes without disentanglement of the sewing thread and the winding thread.
Conventionally, the winding of the general thread around the sewing thread of the button in order to satisfy the above requirements was achieved by a manual manipulation. That is, the sewing thread protruded from the rear surface of the button is wounded by the general thread manually, and is then knotted. The above conventional method is disadvantageous in that it is complicated and requires a long time.
Many solutions to solve the above problems were developed, and a special thread, which does not requiring knotting, has been developed. The above special thread is an elastic thread made of plastic material such as elastomer. The elastic thread is advantageous in that it has a designated adhesivity and thus is not unwound without knot, but is disadvantageous in that it is unwound because it loses its adhesivity after washing several times. Further, the elastic thread is expensive compared to the general thread. Thus, apparatus for winding and knotting a general thread around a sewing thread of a button for clothes, which is cheaper than the elastic thread, are being developed now, and many patents and utility models regarding to such the apparatus have been filed.
FIG. 1 is a schematic view illustrating a method for winding and knotting a thread around a sewing thread of a button for clothes using a conventional knotting apparatus.
As shown in FIG. 1, a button for clothes 1 is sewed to clothes 2 by a sewing thread 3. A general thread 4, which winds a portion of the sewing thread 3 protruded from the rear surface of the button 1, is twisted once per winding. Thereby, a knot 5 is formed each winding of the general thread 4 around the sewing thread 3.
Since the knot 5, which is formed each winding of the general thread 4 around the sewing thread 3, is obtained not by plaiting the general thread 4 but by twisting the general thread 4, when one end of the general thread 4 is drawn, the knots 5 of the general thread 4 are easily disentangled. Further, when the general thread 4 with the knots 5 winding the sewing thread 3 is fixed to the sewing thread 3, the general thread 4 is easily separated from the sewing thread 3. In order to solve the above separation of the general thread 4 from the sewing thread 3, an additional air blast device, for blowing the general thread 4 toward the sewing thread 3, is required.